@end itemize
+@section fftfilt
+Apply arbitrary expressions to samples in frequency domain
+
+@table @option
+@item dc_Y
+Adjust the dc value (gain) of the luma plane of the image. The filter
+accepts an integer value in range @code{0} to @code{1000}. The default
+value is set to @code{0}.
+
+@item dc_U
+Adjust the dc value (gain) of the 1st chroma plane of the image. The
+filter accepts an integer value in range @code{0} to @code{1000}. The
+default value is set to @code{0}.
+
+@item dc_V
+Adjust the dc value (gain) of the 2nd chroma plane of the image. The
+filter accepts an integer value in range @code{0} to @code{1000}. The
+default value is set to @code{0}.
+
+@item weight_Y
+Set the frequency domain weight expression for the luma plane.
+
+@item weight_U
+Set the frequency domain weight expression for the 1st chroma plane.
+
+@item weight_V
+Set the frequency domain weight expression for the 2nd chroma plane.
+
+The filter accepts the following variables:
+@item X
+@item Y
+The coordinates of the current sample.
+
+@item W
+@item H
+The width and height of the image.
+@end table
+
@section field
Extract a single field from an interlaced image using stride
Default value is @var{full}.
@end table
+The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
+(@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
+color quantization of the palette. This information is also visible at
+@var{info} logging level.
+
@subsection Examples
@itemize
the default flags.
@item size, s
-Set the video size. For the syntax of this option, check the "Video size"
-section in the ffmpeg-utils manual.
+Set the video size. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
@item in_color_matrix
@item out_color_matrix
@var{num}/@var{den}.
@item s
-The size of the input frame. For the syntax of this option, check the "Video size"
-section in the ffmpeg-utils manual.
+The size of the input frame. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
@item i
The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
@item original_size
Specify the size of the original video, the video for which the ASS file
-was composed. For the syntax of this option, check the "Video size" section in
-the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
-this is necessary to correctly scale the fonts if the aspect ratio has been
-changed.
+was composed. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
+correctly scale the fonts if the aspect ratio has been changed.
@item charenc
Set subtitles input character encoding. @code{subtitles} filter only. Only
@item layout
Set the grid size (i.e. the number of lines and columns). For the syntax of
-this option, check the "Video size" section in the ffmpeg-utils manual.
+this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
@item nb_frames
Set the maximum number of frames to render in the given area. It must be less
@item video_size
Specify the size (width and height) of the buffered video frames. For the
-syntax of this option, check the "Video size" section in the ffmpeg-utils
-manual.
+syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
@item width
The input video width.
Default value is 110.
@item size, s
-Set the size of the output video. For the syntax of this option, check
-the "Video size" section in the ffmpeg-utils manual.
+Set the size of the output video. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
If @option{filename} or @option{pattern} is specified, the size is set
by default to the width of the specified initial state row, and the
@item size
The size of the video to generate. For the syntax of this option, check the
-"Video size" section in the ffmpeg-utils manual.
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
@item framerate
The framerate of the generated video. It may be a string of the form
@item size, s
Set the size of the output video. For the syntax of this option, check the
-"Video size" section in the ffmpeg-utils manual.
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
If @option{filename} is specified, the size is set by default to the
same size of the input file. If @option{size} is set, it must contain
@item size, s
Specify the size of the sourced video. For the syntax of this option, check the
-"Video size" section in the ffmpeg-utils manual. The default value is
-"320x240".
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+The default value is @code{320x240}.
This option is not available with the @code{haldclutsrc} filter.
Default value is @samp{lissajous}.
@item size, s
-Set the video size for the output. For the syntax of this option, check the "Video size"
-section in the ffmpeg-utils manual. Default value is @code{400x400}.
+Set the video size for the output. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+Default value is @code{400x400}.
@item rate, r
Set the output frame rate. Default value is @code{25}.
@item size
Set the video size. This option is for video only. For the syntax of this
-option, check the "Video size" section in the ffmpeg-utils manual. Default
-and minimum resolution is @code{640x480}.
+option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+Default and minimum resolution is @code{640x480}.
@item meter
Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
@table @option
@item size, s
-Specify the video size for the output. For the syntax of this option, check
-the "Video size" section in the ffmpeg-utils manual. Default value is
-@code{640x512}.
+Specify the video size for the output. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+Default value is @code{640x512}.
@item slide
Specify how the spectrum should slide along the window.
@table @option
@item size, s
-Specify the video size for the output. For the syntax of this option, check
-the "Video size" section in the ffmpeg-utils manual. Default value
-is "600x240".
+Specify the video size for the output. For the syntax of this option, check the
+@ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
+Default value is @code{600x240}.
@item mode
Set display mode.